4 million new asthma cases a year globally among those aged one to 18 are caused by levels of nitrogen dioxide (NO2) in the air.
67,000 new cases of asthma in children across 18 European countries could be prevented every year if levels of tiny particulates polluting the air are cut to recommended levels, 10,400 of which would be in the UK
“A considerable proportion of childhood asthma is actually caused by air pollution, particularly PM2.5,” said Dr Mark Nieuwenhuijsen, from the Barcelona Institute of Global Health (ISGlobal) and a co-author of the research.
The study shows thousands of new cases of asthma could be prevented each year by adhering to guidelines set by the World Health Organization (WHO), but Nieuwenhuijsen and his colleagues write that there is more to do. According to WHO guidelines, levels of PM2.5 should not exceed an annual average of 10 μg/m3, and levels of NO2 should not exceed an annual average of 40 μg/m3.
Prof Stephen Holgate, a special adviser on air quality for the Royal College of Physicians, said the study showed meeting WHO air pollution limits would create a “massive health gain”.
Evidence suggests there is no threshold level when it comes to the impact of air pollution on health, they say.
Nieuwenhuijsen said, “What is clear from our analysis is that current WHO standards are not strict enough to protect against many cases of childhood asthma.”
Dr Susan Anenberg from George Washington University, a co-author of the global study published in April, said, “Almost no one on planet Earth breathes clean air.”